600GB 10,000rpm Hard Drive $100(expired)
Western Digital VelociRaptor 600GB 10,000rpm Hard Drive is on sale for $100 today.
Few people will have a need for a 600GB hard drive that costs $0.17 per GB (most hard drives go for $0.04 to $0.06 per GB), but the 10,000rpm speed means its access time is better than most hard drives, and very good for large databases.
This is an enterprise-class drive, so it includes a 5 year warranty (most hard drives include a 1, 2, or 3 year warranty).
Hard drives will not be as fast as a Solid State Drive (SSD), but SSDs are more expensive (around $0.50 to $0.80 per GB), and are susceptible to performance degradation especially after thousands of hours of heavy writes/deletes of data.
When an SSD is used with a hardware RAID controller though, performance degradation can happen quicker because hardware RAID does not support TRIM.
What does all this mean?
For a server (such as a webserver, database server, or a computer that needs fast performance and great reliability), hard drives are recommended and 10,000rpm drives will perform better.
For a personal computer (such as a desktop or laptop), an SSD would be perfect because of its fast performance, quiet operation, reliability, and gives off zero heat.
If you do need a lot of storage in your computers, look into a 2TB or 3TB drive which will have pretty good performance and a great value at around 4 cents per GB.